The present invention is a closure on a rectangular container for pourable consumer products wherein the closure is folded and heat sealed in a way that the closure easily can be opened into a pour spout for pouring out the content under full control. By folding back the slightly larger triangular pour spout area than the triangular closure opening, the closure is resealed air tight. The new container design provides; consumer friendly usage, reduced materials consumption, high efficiency from production capacity and distribution view points. State of the art containers for liquid products generally have an injection molded pour and cap re-close attachment made of polymer material heat sealed (for some container types comprising 4 injection molded parts) onto the container top panel in order to improve consumer acceptance.
The present invention is providing a controlled tearing path, between an in depth scoring line (beyond container food content) and an 180° folded Polyethylene coated paper board edge of two superimposed and heat sealed Polyethylene (PE) coated paper board panels.
In first index station the rectangular paper board tube structure is pushed onto an indexing mandrel, (rotating with eight mandrels) and in the second index station a film strip is cut off and partially sealed inside 0ne of the paper board tube structures longer mid closure edges. Third and fourth index stations are heat activated by a nozzle/manifold moving over the sealing area with a hot air stream and having multiple specific sealing patterns inside and outside rectangular paper board sleeve sealing area until heat activation finished. Between fourth and fifth index station, the two rectangular paper board tube structures longer panels (third and fourth fades) are pre-folded towards the cartons center (by two rotating folders), one panel including the film strip before the other panel and guided under two stationary guides before reaching the final fold configuration under a compression plate in fifth index station, having different levels (a pattern) with at least on integrated spring loaded element, for finally sealing the closure air tight & liquid proof. Sixth and eight index station are blind stations. In index station seven, the paper board structure with the sealed carton closure is pushed into an indexing pocket belt where the cartons later are filled (upside down) and finally the carton bottom is sealed. Both sides polyethylene (PE) coated paper board is normally used, but also one side polyethylene (PE) coated paper board could be used in combination with a hot melt polymer liquid sealant. When using a multi-polymer-laminate including aluminum foil, induction sealing could eventually be considered. Ultra Sonic sealing is a third option, that eventually also could be considered. By using plain paper board without polymer coating, hot melt is used for sealing the entire carton. For an aseptic carton version, skiving and hemming of the 5th panel is required.
U.S. Pat. No. 3,145,899 provide a container with a permanent film element sealed into the paper board container bottom which is not intended to be opened, but providing a permanent bottom seal of the container. In order to push a container with a rectangular cross section onto a mandrel in a production machine, a tolerance is needed between the container and the mandrel cross sections; otherwise one of the panel walls of a container will be destructed when pushing the container onto the mandrel. Heat sealing four folded down film element sides to four container panel walls, require that the cross section inside the container and the mandrel are more or less identical, otherwise the film element will be too small and the film element will be under tension from the large container cross section and come loose, resulting in leaking containers.
According to European Patent #0511358 B1, a Polyethylene (PE) film element is placed onto a mandrel surface with the objective of folding a container over the mandrel and heat seal the film element inside the container closure in a way that the Polyethylene (PE) film breaks along two of the container closures straight paper board folding lines when opening the container. A major obstacle with this container closure design is that a minor liquid channel in the film element edge area where the paper board is folded 180° could not be heat sealed liquid proof. Substantial engineering capacity over a very long period of time could not resolve this problem and it was decided not to commercialize this container design. Distribution tests furthermore proved that the Polyethylene (PE) film does not withhold the tension on the film element throughout the entire distribution route and the film element fractures, resulting in leaking containers. Several stronger multi-laminate film element structures having different material types including different layer combinations have been tested without success. Consumer panel tests prove that containers with stronger film elements could not be opened as consumers did not have the sufficient strength to break the film element.